Fish Leech (Piscicola Geometra)

Piscicola Geometra is the most common leech found in garden ponds, generally introduced on plants. It is referred to as one of the few 'true parasites' meaning it penetrates the skin and feeds off the blood and tissue of the fish - resulting in significant damage which if unchecked will result in death.The fish leech is sometimes confused with midge larva which are often found in filters and on the sides of the pond.  They are harmless and much shorter in length than Piscicola Geomeytra which can measure up to 25mm long and can be seen from a considerable distance.  Once it has attached itself to the Koi to feed, it can drop off for up to several weeks, only returning to feed.  The Leech is a strong swimmer and can visibly be seen swimming to it's victim.  The leech has to leave the Koi to perform it's egg laying function, completing it's life cycle can take up to 30 days.

Although chemicals can be used, removing the leeches and placing the fish in a 'leech free' facility offers an alternative with a greater success rate of total eradication. Salt can be added to assist recovery and minimise the risk of secondary infections. The pond should be left empty of fish for approx 4 weeks to eridicate both stages of the leeches life cycle. Another option is to completely drain the pond, although this is not always practical especially if your pond is a considerable size, leaving it to dry out will destory both the adult leeches and eggs.